Dispersant additives are used to suspend oil-insoluble resinous oxidation products and particulate contaminants in the bulk oil. Ideally, this minimizes sludge formation, particulate-related wear, viscosity increase, and oxidation-related deposit formation. Dispersants are primarily used in gasoline engine and heavy-duty diesel engine oils. They are also used in natural gas engine oils, aviation piston engine oils, automatic transmission fluids and some types of gear lubricants. A variety of commercial dispersant additives have been available and used. For instance, N-substituted long-chain alkenyl succinimides have been used as ashless dispersants. An alkenylsuccinic acid intermediate is obtained by condensing an olefin polymer, such as polyisobutylene, with maleic anhydride. A basic part of the dispersant additive has then been obtained, e.g., from reacting the intermediate with amine compounds such as polyamines. Other previously used dispersants include high molecular weight esters, e.g., a reaction product of an alkylene glycol and a substituted succinic anhydride. Other known dispersants include Mannich bases obtained from high molecular weight alkylated phenols, such as, e.g., the reaction product of a polyalkylenephenol, polyalkylenepolyamine, and an aldehyde. Oil chemists are continually searching for dispersants that achieve optimum dispersancy and low-temperature performance at low concentrations. The present invention addresses the need for improved dispersants for lubricating oils and fluids.